<?php

while($row = mysqli_fetch_assoc($sql)) {
    ....
    $array_tmp = array();

    $array_tmp["black_0"] = $black;
    $array_tmp["red_1"  ] = $red;
    $array_tmp["blue_1" ] = $blue;
};

$dataset[] = $array_tmp;

echo json_encode($dataset, JSON_UNESCAPED_UNICODE);

?>

$.ajax({
   ...
   success: function(response){
        dataSet = JSON.parse(response);

        $.each(dataSet[0], function(key, value){
            var active = key.substr(key.length - 1);
        });
   }
});